#include <linux/mm_inline.h>
#include <linux/nsproxy.h>
#include <linux/pagevec.h>
+#include <linux/ksm.h>
#include <linux/rmap.h>
#include <linux/topology.h>
#include <linux/cpu.h>
#include <linux/security.h>
#include <linux/memcontrol.h>
#include <linux/syscalls.h>
+#include <linux/gfp.h>
#include "internal.h"
/*
* migrate_prep() needs to be called before we start compiling a list of pages
- * to be migrated using isolate_lru_page().
+ * to be migrated using isolate_lru_page(). If scheduling work on other CPUs is
+ * undesirable, use migrate_prep_local()
*/
int migrate_prep(void)
{
return 0;
}
+/* Do the necessary work of migrate_prep but not if it involves other CPUs */
+int migrate_prep_local(void)
+{
+ lru_add_drain();
+
+ return 0;
+}
+
/*
* Add isolated pages on the list back to the LRU under page lock
* to avoid leaking evictable pages back onto unevictable list.
- *
- * returns the number of pages put back.
*/
-int putback_lru_pages(struct list_head *l)
+void putback_lru_pages(struct list_head *l)
{
struct page *page;
struct page *page2;
- int count = 0;
list_for_each_entry_safe(page, page2, l, lru) {
list_del(&page->lru);
+ dec_zone_page_state(page, NR_ISOLATED_ANON +
+ page_is_file_cache(page));
putback_lru_page(page);
- count++;
}
- return count;
}
/*
* Restore a potential migration pte to a working pte entry
*/
-static void remove_migration_pte(struct vm_area_struct *vma,
- struct page *old, struct page *new)
+static int remove_migration_pte(struct page *new, struct vm_area_struct *vma,
+ unsigned long addr, void *old)
{
struct mm_struct *mm = vma->vm_mm;
swp_entry_t entry;
pmd_t *pmd;
pte_t *ptep, pte;
spinlock_t *ptl;
- unsigned long addr = page_address_in_vma(new, vma);
-
- if (addr == -EFAULT)
- return;
pgd = pgd_offset(mm, addr);
if (!pgd_present(*pgd))
- return;
+ goto out;
pud = pud_offset(pgd, addr);
if (!pud_present(*pud))
- return;
+ goto out;
pmd = pmd_offset(pud, addr);
if (!pmd_present(*pmd))
- return;
+ goto out;
ptep = pte_offset_map(pmd, addr);
if (!is_swap_pte(*ptep)) {
pte_unmap(ptep);
- return;
+ goto out;
}
ptl = pte_lockptr(mm, pmd);
spin_lock(ptl);
pte = *ptep;
if (!is_swap_pte(pte))
- goto out;
+ goto unlock;
entry = pte_to_swp_entry(pte);
- if (!is_migration_entry(entry) || migration_entry_to_page(entry) != old)
- goto out;
+ if (!is_migration_entry(entry) ||
+ migration_entry_to_page(entry) != old)
+ goto unlock;
get_page(new);
pte = pte_mkold(mk_pte(new, vma->vm_page_prot));
page_add_file_rmap(new);
/* No need to invalidate - it was non-present before */
- update_mmu_cache(vma, addr, pte);
-
-out:
+ update_mmu_cache(vma, addr, ptep);
+unlock:
pte_unmap_unlock(ptep, ptl);
-}
-
-/*
- * Note that remove_file_migration_ptes will only work on regular mappings,
- * Nonlinear mappings do not use migration entries.
- */
-static void remove_file_migration_ptes(struct page *old, struct page *new)
-{
- struct vm_area_struct *vma;
- struct address_space *mapping = page_mapping(new);
- struct prio_tree_iter iter;
- pgoff_t pgoff = new->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT);
-
- if (!mapping)
- return;
-
- spin_lock(&mapping->i_mmap_lock);
-
- vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, pgoff, pgoff)
- remove_migration_pte(vma, old, new);
-
- spin_unlock(&mapping->i_mmap_lock);
-}
-
-/*
- * Must hold mmap_sem lock on at least one of the vmas containing
- * the page so that the anon_vma cannot vanish.
- */
-static void remove_anon_migration_ptes(struct page *old, struct page *new)
-{
- struct anon_vma *anon_vma;
- struct vm_area_struct *vma;
- unsigned long mapping;
-
- mapping = (unsigned long)new->mapping;
-
- if (!mapping || (mapping & PAGE_MAPPING_ANON) == 0)
- return;
-
- /*
- * We hold the mmap_sem lock. So no need to call page_lock_anon_vma.
- */
- anon_vma = (struct anon_vma *) (mapping - PAGE_MAPPING_ANON);
- spin_lock(&anon_vma->lock);
-
- list_for_each_entry(vma, &anon_vma->head, anon_vma_node)
- remove_migration_pte(vma, old, new);
-
- spin_unlock(&anon_vma->lock);
+out:
+ return SWAP_AGAIN;
}
/*
*/
static void remove_migration_ptes(struct page *old, struct page *new)
{
- if (PageAnon(new))
- remove_anon_migration_ptes(old, new);
- else
- remove_file_migration_ptes(old, new);
+ rmap_walk(new, remove_migration_pte, old);
}
/*
pslot = radix_tree_lookup_slot(&mapping->page_tree,
page_index(page));
- expected_count = 2 + !!page_has_private(page);
+ expected_count = 2 + page_has_private(page);
if (page_count(page) != expected_count ||
(struct page *)radix_tree_deref_slot(pslot) != page) {
spin_unlock_irq(&mapping->tree_lock);
*/
__dec_zone_page_state(page, NR_FILE_PAGES);
__inc_zone_page_state(newpage, NR_FILE_PAGES);
-
+ if (PageSwapBacked(page)) {
+ __dec_zone_page_state(page, NR_SHMEM);
+ __inc_zone_page_state(newpage, NR_SHMEM);
+ }
spin_unlock_irq(&mapping->tree_lock);
return 0;
*/
static void migrate_page_copy(struct page *newpage, struct page *page)
{
- int anon;
-
copy_highpage(newpage, page);
if (PageError(page))
if (TestClearPageActive(page)) {
VM_BUG_ON(PageUnevictable(page));
SetPageActive(newpage);
- } else
- unevictable_migrate_page(newpage, page);
+ } else if (TestClearPageUnevictable(page))
+ SetPageUnevictable(newpage);
if (PageChecked(page))
SetPageChecked(newpage);
if (PageMappedToDisk(page))
}
mlock_migrate_page(newpage, page);
+ ksm_migrate_page(newpage, page);
ClearPageSwapCache(page);
ClearPagePrivate(page);
set_page_private(page, 0);
- /* page->mapping contains a flag for PageAnon() */
- anon = PageAnon(page);
page->mapping = NULL;
/*
* < 0 - error code
* == 0 - success
*/
-static int move_to_new_page(struct page *newpage, struct page *page)
+static int move_to_new_page(struct page *newpage, struct page *page,
+ int remap_swapcache)
{
struct address_space *mapping;
int rc;
else
rc = fallback_migrate_page(mapping, newpage, page);
- if (!rc) {
- remove_migration_ptes(page, newpage);
- } else
+ if (rc) {
newpage->mapping = NULL;
+ } else {
+ if (remap_swapcache)
+ remove_migration_ptes(page, newpage);
+ }
unlock_page(newpage);
* to the newly allocated page in newpage.
*/
static int unmap_and_move(new_page_t get_new_page, unsigned long private,
- struct page *page, int force)
+ struct page *page, int force, int offlining)
{
int rc = 0;
int *result = NULL;
struct page *newpage = get_new_page(page, private, &result);
+ int remap_swapcache = 1;
int rcu_locked = 0;
int charge = 0;
- struct mem_cgroup *mem;
+ struct mem_cgroup *mem = NULL;
+ struct anon_vma *anon_vma = NULL;
if (!newpage)
return -ENOMEM;
lock_page(page);
}
+ /*
+ * Only memory hotplug's offline_pages() caller has locked out KSM,
+ * and can safely migrate a KSM page. The other cases have skipped
+ * PageKsm along with PageReserved - but it is only now when we have
+ * the page lock that we can be certain it will not go KSM beneath us
+ * (KSM will not upgrade a page from PageAnon to PageKsm when it sees
+ * its pagecount raised, but only here do we take the page lock which
+ * serializes that).
+ */
+ if (PageKsm(page) && !offlining) {
+ rc = -EBUSY;
+ goto unlock;
+ }
+
/* charge against new page */
charge = mem_cgroup_prepare_migration(page, &mem);
if (charge == -ENOMEM) {
if (PageAnon(page)) {
rcu_read_lock();
rcu_locked = 1;
+
+ /* Determine how to safely use anon_vma */
+ if (!page_mapped(page)) {
+ if (!PageSwapCache(page))
+ goto rcu_unlock;
+
+ /*
+ * We cannot be sure that the anon_vma of an unmapped
+ * swapcache page is safe to use because we don't
+ * know in advance if the VMA that this page belonged
+ * to still exists. If the VMA and others sharing the
+ * data have been freed, then the anon_vma could
+ * already be invalid.
+ *
+ * To avoid this possibility, swapcache pages get
+ * migrated but are not remapped when migration
+ * completes
+ */
+ remap_swapcache = 0;
+ } else {
+ /*
+ * Take a reference count on the anon_vma if the
+ * page is mapped so that it is guaranteed to
+ * exist when the page is remapped later
+ */
+ anon_vma = page_anon_vma(page);
+ atomic_inc(&anon_vma->external_refcount);
+ }
}
/*
* needs to be effective.
*/
try_to_free_buffers(page);
+ goto rcu_unlock;
}
- goto rcu_unlock;
+ goto skip_unmap;
}
/* Establish migration ptes or remove ptes */
- try_to_unmap(page, 1);
+ try_to_unmap(page, TTU_MIGRATION|TTU_IGNORE_MLOCK|TTU_IGNORE_ACCESS);
+skip_unmap:
if (!page_mapped(page))
- rc = move_to_new_page(newpage, page);
+ rc = move_to_new_page(newpage, page, remap_swapcache);
- if (rc)
+ if (rc && remap_swapcache)
remove_migration_ptes(page, page);
rcu_unlock:
+
+ /* Drop an anon_vma reference if we took one */
+ if (anon_vma && atomic_dec_and_lock(&anon_vma->external_refcount, &anon_vma->lock)) {
+ int empty = list_empty(&anon_vma->head);
+ spin_unlock(&anon_vma->lock);
+ if (empty)
+ anon_vma_free(anon_vma);
+ }
+
if (rcu_locked)
rcu_read_unlock();
uncharge:
* restored.
*/
list_del(&page->lru);
+ dec_zone_page_state(page, NR_ISOLATED_ANON +
+ page_is_file_cache(page));
putback_lru_page(page);
}
* Return: Number of pages not migrated or error code.
*/
int migrate_pages(struct list_head *from,
- new_page_t get_new_page, unsigned long private)
+ new_page_t get_new_page, unsigned long private, int offlining)
{
int retry = 1;
int nr_failed = 0;
cond_resched();
rc = unmap_and_move(get_new_page, private,
- page, pass > 2);
+ page, pass > 2, offlining);
switch(rc) {
case -ENOMEM:
*result = &pm->status;
- return alloc_pages_node(pm->node,
+ return alloc_pages_exact_node(pm->node,
GFP_HIGHUSER_MOVABLE | GFP_THISNODE, 0);
}
struct page_to_node *pp;
LIST_HEAD(pagelist);
- migrate_prep();
down_read(&mm->mmap_sem);
/*
if (!page)
goto set_status;
- if (PageReserved(page)) /* Check for zero page */
+ /* Use PageReserved to check for zero page */
+ if (PageReserved(page) || PageKsm(page))
goto put_and_set;
pp->page = page;
goto put_and_set;
err = isolate_lru_page(page);
- if (!err)
+ if (!err) {
list_add_tail(&page->lru, &pagelist);
+ inc_zone_page_state(page, NR_ISOLATED_ANON +
+ page_is_file_cache(page));
+ }
put_and_set:
/*
* Either remove the duplicate refcount from
err = 0;
if (!list_empty(&pagelist))
err = migrate_pages(&pagelist, new_page_node,
- (unsigned long)pm);
+ (unsigned long)pm, 0);
up_read(&mm->mmap_sem);
return err;
pm = (struct page_to_node *)__get_free_page(GFP_KERNEL);
if (!pm)
goto out;
+
+ migrate_prep();
+
/*
* Store a chunk of page_to_node array in a page,
* but keep the last one as a marker
goto out_pm;
err = -ENODEV;
+ if (node < 0 || node >= MAX_NUMNODES)
+ goto out_pm;
+
if (!node_state(node, N_HIGH_MEMORY))
goto out_pm;
err = -ENOENT;
/* Use PageReserved to check for zero page */
- if (!page || PageReserved(page))
+ if (!page || PageReserved(page) || PageKsm(page))
goto set_status;
err = page_to_nid(page);
#define DO_PAGES_STAT_CHUNK_NR 16
const void __user *chunk_pages[DO_PAGES_STAT_CHUNK_NR];
int chunk_status[DO_PAGES_STAT_CHUNK_NR];
- unsigned long i, chunk_nr = DO_PAGES_STAT_CHUNK_NR;
- int err;
- for (i = 0; i < nr_pages; i += chunk_nr) {
- if (chunk_nr + i > nr_pages)
- chunk_nr = nr_pages - i;
+ while (nr_pages) {
+ unsigned long chunk_nr;
- err = copy_from_user(chunk_pages, &pages[i],
- chunk_nr * sizeof(*chunk_pages));
- if (err) {
- err = -EFAULT;
- goto out;
- }
+ chunk_nr = nr_pages;
+ if (chunk_nr > DO_PAGES_STAT_CHUNK_NR)
+ chunk_nr = DO_PAGES_STAT_CHUNK_NR;
+
+ if (copy_from_user(chunk_pages, pages, chunk_nr * sizeof(*chunk_pages)))
+ break;
do_pages_stat_array(mm, chunk_nr, chunk_pages, chunk_status);
- err = copy_to_user(&status[i], chunk_status,
- chunk_nr * sizeof(*chunk_status));
- if (err) {
- err = -EFAULT;
- goto out;
- }
- }
- err = 0;
+ if (copy_to_user(status, chunk_status, chunk_nr * sizeof(*status)))
+ break;
-out:
- return err;
+ pages += chunk_nr;
+ status += chunk_nr;
+ nr_pages -= chunk_nr;
+ }
+ return nr_pages ? -EFAULT : 0;
}
/*
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff